背景线索和认知风格对真实场景中目标搜索影响的眼动研究

采用眼动记录方法,研究背景线索和认知风格对真实场景中目标搜索三阶段的影响。实验以真实的室内场景图片为材料,通过重复呈现整体背景一致或局部背景一致的场景,考察不同场认知风格被试在整体背景线索和局部背景线索条件下在目标搜索各阶段的眼动特征。结果表明,整体背景线索和局部背景线索对目标搜索的启动和确认阶段没有影响,对扫描阶段有促进作用,且整体背景线索效应大于局部背景线索效应,主要体现在能更有效地选择注视区域,在单次注视中获得更多的信息,更迅速地拒绝当前注视区域和计划下一次眼跳;认知风格不影响个体在真实场景目标搜索过程中对背景线索的利用。     

真实场景视觉搜索中的背景线索效应特点与机制

背景线索效应揭示了个体在视觉搜索过程中对刺激之间具有的稳定空间关系（刺激间不变的相对空间位置）的学习能够提高搜索效率。本文基于经典背景线索效应在内隐习得空间布局的机制下结合真实场景视觉搜索的相关理论，对真实场景背景线索效应的实验范式、学习性质与内容进行归纳梳理，将真实场景视觉搜索中影响背景线索效应的视觉信息分为低水平物理特征及高水平语义信息两个维度进行论述。虽然当前研究涉及真实场景背景线索效应在不同场景维度信息的加工机制，但对于发挥作用的场景信息类别以及作用阶段还较少涉及，未来研究仍需进一步的探讨。     

在真实场景中记忆对学龄儿童注意的导向

采用背景线索范式,探讨在真实场景中记忆对学龄儿童的注意导向。结果发现：（1）搜索任务中,学龄儿童在重复场景中的目标搜索随着学习阶段的增加而得到促进,获得显著的背景线索效应,但在新异场景中却没有出现。（2）回忆任务中,学龄儿童对重复场景及其共变目标位置的记忆好于对新异场景的,且显著地高于随机水平。结果表明,在真实场景中,对背景及目标-背景共变关系的记忆引导着学龄儿童的注意分布,且该引导随着经验的增加而变得更有效;该记忆具有外显性。     

基于双眼视差探讨深度知觉信息对背景线索效应的影响

背景线索效应是由重复场景导致搜索效率提高的现象。以往研究发现三维场景下能获得背景线索效应,但对三维场景下深度知觉线索信息如何影响空间场景提供有效线索引导注意仍缺乏实证研究。本研究以矩阵刺激为材料,通过设置不同的刺激项目水平数探讨深度知觉线索对背景线索效应的影响模式。结果发现:(1)在场景布局由较少项目构成时,深度知觉线索提供目标与刺激项目的有效联结,获得背景线索效应;(2)当刺激项目水平达到一定程度时,深度知觉线索增加了背景线索任务的搜索难度,干扰了重复场景中的背景信息对注意的指导性加工,背景线索效应消失。研究结果为三维场景下深度信息对空间场景中注意引导加工的影响提供了证据。     

眼睛注视线索提示效应: 内源性注意还是外源性注意?

采用改进的Posner视-空间线索提示范式, 对眼睛注视线索提示效应(eyes gaze cueing effect)的加工机制进行了探讨。实验一考察注视提示线索对空间Stroop效应的影响; 实验二考察注视提示线索对特征抽取和特征整合的影响。实验结果显示: 注视线索提示有效时的空间Stroop效应显著大于提示无效的情景; 在单一特征搜索与特征联合搜索任务中, 注视线索提示效应无差别。这说明, 注视线索通过在头脑里形成空间方位表征诱导注意转移; 注视线索通过影响特征抽取、而非特征整合阶段, 对客体加工产生易化。本研究支持注视线索提示效应属于内源性注意的观点。     

物体拓扑性质对背景线索效应的影响及其加工机制

背景线索效应是指在视觉搜索中由于场景的重复曝光而产生的行为便利。而以往研究关注于刺激的欧式性质所代表的属性信息对背景线索效应的影响, 然而在视知觉加工过程中扮演重要角色的拓扑性质对背景线索效应的影响仍缺乏相关实证研究。因此, 研究采用视觉搜索任务, 通过操控不同场景中刺激的拓扑性质或欧式性质的变化, 考察拓扑性质与欧式性质两种属性信息对背景线索效应的调制。结果发现：(1)拓扑性质和欧式性质与目标之间的联结关系均可促进行为反应, 获得背景线索效应; (2)视觉学习机制对拓扑性质的重复性更加敏感, 并且拓扑性质与目标之间联结关系的稳定性相对于欧式性质与目标之间的联结关系稳定性对于背景线索效应的获得具有更为重要的意义。     

视空工作记忆负载对真实场景搜索绩效的影响

采用视空工作记忆任务和真实场景搜索任务相结合的双任务范式, 结合眼动技术将搜索过程划分为起始阶段、扫描阶段和确认阶段, 探究视空工作记忆负载对真实场景搜索绩效的影响机制, 同时考查试次间搜索目标是否变化、目标模板的具体化程度以及搜索场景画面的视觉混乱度所起的调节作用。结果表明, 视空工作记忆负载会降低真实场景搜索的成绩, 在搜索过程中表现为视空负载条件下扫描阶段持续时间的延长、注视点数目的增加和空间负载条件下确认阶段持续时间的延长, 视空负载对搜索过程的影响与目标模板的具体化程度有关; 空间负载会降低真实场景搜索的效率, 且与搜索画面的视觉混乱度有关, 而客体负载则不会。由此可见, 视空工作记忆负载对真实场景搜索绩效的影响不同, 空间负载对搜索过程的影响比客体负载更长久, 二者均受到目标模板具体化程度的调节; 仅空间负载会降低真实场景的搜索效率, 且受到搜索场景画面视觉混乱度的调节。     

空间工作记忆负载对真实场景情境提示效应的影响

重复的画面布局能够促进观察者对目标项的搜索 (情境提示效应)。本研究采用双任务范式,分别在视觉搜索任务的学习阶段 (实验2a) 和测验阶段 (实验2b) 加入空间工作记忆任务, 并与单任务基线 (实验1)进行比较, 考察空间工作记忆负载对真实场景搜索中情境线索学习和情境提示效应表达的影响。结果发现: 空间负载会增大学习阶段的情境提示效应量, 同时削弱测验阶段的情境提示效应量, 而不影响情境线索的外显提取。由此可见, 真实场景中情境线索的学习和提示效应的表达均会受到有限的工作记忆资源的影响, 但情境线索提取的外显性不变。     

媒体多任务经验对不同注意模式下内隐记忆的影响

本研究采用经典背景线索范式,在分布式注意（限制眼动）和集中式注意（自由观看）两种模式下考察不同媒体多任务经验者的内隐记忆表现。实验1要求被试在学习阶段自由观看场景并搜索目标,在测试阶段限制眼动并使用外周视野搜索目标。实验2将学习、测试阶段的注意模式反转。结果发现,高媒体多任务经验者在两种注意模式下均表现出背景线索效应;低媒体多任务经验者仅在集中式注意模式下表现出背景线索效应。结果表明,高媒体多任务经验者在分布式注意模式下存在一定的内隐记忆优势。     

二维场景旋转下的背景提示效应

在视觉搜索中,特定背景与目标位置的多次联合呈现能够促进搜索绩效,这被称为背景提示效应。本研究探讨背景提示效应能否迁移到二维旋转后的视觉场景中去。选择大学生为被试,采用2(场景类型:重复、新异)×7(时间阶段:1~7)×3(旋转角度:0°、45°、60°)的三因素混合实验设计。被试在进行背景提示效应的学习后,随机分为三组分别在旋转了0°、45°、60°的场景中继续执行视觉搜索任务。结果发现:三组被试都习得了背景提示效应,且都迁移到了旋转后的场景中。这表明背景提示效应可能存在更高级的编码方式。     

Categorical implicit learning in real-world scenes: evidence from contextual cueing

The present study examined the extent to which learning mechanisms are deployed on semantic-categorical regularities during a visual searching within real-world scenes. The contextual cueing paradigm was used with photographs of indoor scenes in which the semantic category did or did not predict the target position on the screen. No evidence of a facilitation effect was observed in the predictive condition compared to the nonpredictive condition when participants were merely instructed to search for a target T or L (Experiment 1). However, a rapid contextual cueing effect occurred when each display containing the search target was preceded by a preview of the scene on which participants had to make a decision regarding the scene's category (Experiment 2). A follow-up explicit memory task indicated that this benefit resulted from implicit learning. Similar implicit contextual cueing effects were also obtained when the scene to categorize was different from the subsequent search scene (Experiment 3) and when a mere preview of the search scene preceded the visual searching (Experiment 4). These results suggested that if enhancing the processing of the scene was required with the present material, such implicit semantic learning can nevertheless take place when the category is task irrelevant.     

Interaction between scene-based and array-based contextual cueing

Contextual cueing refers to the cueing of spatial attention by repeated spatial context. Previous studies have demonstrated distinctive properties of contextual cueing by background scenes and by an array of search items. Whereas scene-based contextual cueing reflects explicit learning of the scene–target association, array-based contextual cueing is supported primarily by implicit learning. In this study, we investigated the interaction between scene-based and array-based contextual cueing. Participants searched for a target that was predicted by both the background scene and the locations of distractor items. We tested three possible patterns of interaction: (1) The scene and the array could be learned independently, in which case cueing should be expressed even when only one cue was preserved; (2) the scene and array could be learned jointly, in which case cueing should occur only when both cues were preserved; (3) overshadowing might occur, in which case learning of the stronger cue should preclude learning of the weaker cue. In several experiments, we manipulated the nature of the contextual cues present during training and testing. We also tested explicit awareness of scenes, scene–target associations, and arrays. The results supported the overshadowing account: Specifically, scene-based contextual cueing precluded array-based contextual cueing when both were predictive of the location of a search target. We suggest that explicit, endogenous cues dominate over implicit cues in guiding spatial attention.     

Using real-world scenes as contextual cues for search

Research on contextual cueing has demonstrated that with simple arrays of letters and shapes, search for a target increases in efficiency as associations between a search target and its surrounding visual context are learned. We investigated whether the visual context afforded by repeated exposure to real-world scenes can also guide attention when the relationship between the scene and a target position is arbitrary. Observers searched for and identified a target letter embedded in photographs of real-world scenes. Although search time within novel scenes was consistent across trials, search time within repeated scenes decreased across repetitions. Unlike previous demonstrations of contextual cueing, however, memory for scene-target covariation was explicit. In subsequent memory tests, observers recognized repeated contexts more often than those that were presented once and displayed superior recall of target position within the repeated scenes. In addition, repetition of inverted scenes, which made the scene more difficult to identify, produced a markedly reduced rate of learning, suggesting semantic information concerning object and scene identity are used to guide attention.     

Probing attentional modulation of contextual cueing

The repetition of spatial layout implicitly facilitates visual search (contextual cueing effect; Chun & Jiang, 1998). Although a substantial number of studies have explored the mechanism underlying the contextual cueing effect, the manner in which contextual information guides spatial attention to a target location during a visual search remains unclear. We investigated the nature of attentional modulation by contextual cueing, using a hybrid paradigm of a visual search task and a probe dot detection task. In the case of a repeated spatial layout, detection of a probe dot was facilitated at a search target location and was inhibited at distractor locations relative to nonrepeated spatial layouts. Furthermore, these facilitatory and inhibitory effects possessed different learning properties across epochs (Experiment 1) and different time courses within a trial (Experiment 2). These results suggest that contextual cueing modulates attentional processing via both facilitation to the location of “to-be-attended” stimuli and inhibition to the locations of “to-be-ignored” stimuli.     

Selective attention modulates implicit learning

The effect of selective attention on implicit learning was tested in four experiments using the "contextual cueing" paradigm (Chun & Jiang, 1998, 1999). Observers performed visual search through items presented in an attended colour (e.g., red) and an ignored colour (e.g., green). When the spatial configuration of items in the attended colour was invariant and was consistently paired with a target location, visual search was facilitated, showing contextual cueing (Experiments 1, 3, and 4). In contrast, repeating and pairing the configuration of the ignored items with the target location resulted in no contextual cueing (Experiments 2 and 4). We conclude that implicit learning is robust only when relevant, predictive information is selectively attended.     

Contextual cost: When a visual-search target is not where it should be

Visual search is often facilitated when the search display occasionally repeats, revealing a contextual-cueing effect. According to the associative-learning account, contextual cueing arises from associating the display configuration with the target location. However, recent findings emphasizing the importance of local context near the target have given rise to the possibility that low-level repetition priming may account for the contextual-cueing effect. This study distinguishes associative learning from local repetition priming by testing whether search is directed toward a target's expected location, even when the target is relocated. After participants searched for a T among Ls in displays that repeated 24 times, they completed a transfer session where the target was relocated locally to a previously blank location (Experiment 1) or to an adjacent distractor location (Experiment 2). Results revealed that contextual cueing decreased as the target appeared farther away from its expected location, ultimately resulting in a contextual cost when the target swapped locations with a local distractor. We conclude that target predictability is a key factor in contextual cueing.